JPH0583297B2 - - Google Patents

Description

[Detailed description of the invention]

<<Industrial Application Field>> The present invention relates to a method for manufacturing an emulsion type silicone antifoaming agent, and particularly to a continuous manufacturing method. It is known that emulsion-type silicone defoamers can be obtained by emulsifying a silicone oil compound in which finely divided inorganic fillers such as finely powdered silica, titanium dioxide, ammonium oxide, etc. are dispersed in silicone oil (particularly Kosho 58-7335
(Japanese Patent Publication No. 60-35163, Japanese Patent Publication No. 60-52845, Japanese Patent Publication No. 60-262827, Japanese Patent Publication No. 62-277110). The method for producing such an emulsion-type silicone antifoam agent is to mix the silicone oil compound described above with an emulsifier, other additives, and, if necessary, a thickener, and to finely stir this mixture until a homogeneous dispersion is obtained. A common process is to crush the homogeneous dispersion, and then add water to the homogeneous dispersion while applying strong shearing force to form an emulsion. In this case, it is necessary to use a mixer with a high shear rate in order to add water to the homogeneous dispersion and invert the phase from W/O type to O/W type, but such equipment includes a colloid mill, Homogenizers, homomixers, and the like are known (Japanese Patent Application Laid-Open No. 52-2886, Japanese Patent Publication No. 60-35163). However, if we take as an example a method that uses a stirrer equipped with a high-speed shearing stirring blade and a stator, usually called a homomixer, the emulsified material is sucked through at least the holes provided in the stator, and the shearing action of the high-speed rotary blade is used. However, as mentioned above, in order for the material to be emulsified to be sucked through the pores, the viscosity must be at most 10,000 cp or less, so there is a limit to the viscosity of the dispersion that can be emulsified. . In particular, since finely powdered silica is dispersed in the silicone antifoam composition, it is thicker than the base silicone oil and is difficult to emulsify. Therefore, even if the viscosity of the antifoam composition is within an appropriate range, the viscosity may increase significantly when adding an emulsifier or a small amount of water to transform the phase from W/O type to O/W type. This naturally placed a limit on the composition that could be emulsified. The above-mentioned drawbacks of the homomixer can also be pointed out with respect to colloid mills and homogenizers. As a method to eliminate such drawbacks, (A) a stirring means that can rotate the contents at low speed throughout the container;
(B) Disk type stirring means with tooth-like projections on the periphery and (C)
Method for manufacturing an emulsion-type silicone antifoaming agent using a composite stirring device comprising a stirring means having a stator and high-speed turbine blades (Japanese Patent Application Laid-Open No. 63-182002
According to this method, 100,000
It is said that it is also possible to emulsify high viscosity silicone oil compounds with a CP or higher viscosity. However, when such an apparatus is used, it is not possible to continuously emulsify the silicone antifoam composition to obtain an emulsion, and sufficient production efficiency cannot be obtained. On the other hand, a continuous production method for silicone emulsion is characterized in that polydiorganosiloxane, emulsifier, and water are continuously supplied into a cylindrical container equipped with a shear stirring mechanism, and a grease-like aqueous silicone liquid is continuously taken out. A manufacturing method has been disclosed (Japanese Patent Publication No. 59-51565), and it is said that when polydiorganosiloxane, emulsifier, and water are added in predetermined proportions, fine silica powder can be added together if necessary. There is. However, this method continuously emulsifies silicone oil to provide a silicone emulsion that can be used as a mold release agent, polishing agent, medical ointment, cosmetic base, etc. Even if an emulsion containing fine silica powder is produced by adding powder during production, the antifoaming effect is extremely weak because the silicone oil emulsion and fine silica powder exist in a dispersed state. In some cases, it also exhibits properties as a foam. As a result of intensive studies to solve the conventional drawbacks, the inventors of the present invention have developed a method to continuously produce an emulsion-type silicone antifoaming agent by mixing organopolysiloxane and finely powdered silica in advance prior to emulsification and dispersion. The present invention was achieved by discovering that this can be done. <<Problems to be Solved by the Invention>> Accordingly, an object of the present invention is to provide a continuous method for producing an emulsion type silicone antifoaming agent. <Means for Solving the Problems> The above object of the present invention is to provide (a) 100 parts by weight of a silicone oil compound consisting of 100 parts by weight of organopolysiloxane and 1 to 40 parts by weight of finely powdered silica;
(b) Emulsifier: 10 to 300 parts by weight, (c) Water: 10 to 560 parts by weight, and (d) Thickener: 0 to 20 parts by weight in a cylindrical container equipped with a shear stirring mechanism. While supplying and maintaining the inside of the container in a pressurized state of 0.5Kg/cm ² G or more,
A method for continuous production of an emulsion-type silicone antifoaming agent characterized in that after performing shear stirring at a shear rate of 50 (1/sec) or more, the silicone emulsion is continuously taken out from the product outlet of the container. was achieved. The shear stirring mechanism is characterized in that at least three disks are arranged coaxially and at regular intervals on a rotating shaft coaxially installed with the cylindrical container. The method of the present invention will be explained in detail below. The organopolysiloxane (component (a)) used in the emulsion-type silicone antifoaming agent of the present invention is represented by the general formula R ¹ _a SiO _4-a/2 , where R ¹ is a methyl group, an ethyl group, a propyl group, or a butyl group. Alkyl groups such as vinyl groups, alkenyl groups such as allyl groups, aryl groups such as phenyl groups and tolyl groups, and some or all of the hydrogen atoms bonded to the carbon atoms of these groups are halogen atoms, cyano groups, etc. Substituted chloromethyl group, 3,3,3-
The same or different unsubstituted or substituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, such as trifluoropropyl group, cyanopropyl group, etc., a is the average value of
It is 1.9-2.1. Examples of the organopolysiloxane include dimethylpolysiloxane, diethylpolysiloxane, methylphenylpolysiloxane, polydimethyl-polydiphenylsiloxane copolymer, polymethyl-3,3,3-trifluoropropylsiloxane, polydimethyl-chloropropylmethyl Examples include siloxane. The finely powdered silica added to this organopolysiloxane may be either dry silica or wet silica, which have been conventionally known as silica-based fillers, such as precipitated silica, silica xerogel, fumed silica, and organic fillers. Treated silica treated with a silyl group, etc. can be used. Specific examples of such fine powder silica include Aerosil (trade name manufactured by Nippon Aerosil Co., Ltd.), Nipsil (trade name manufactured by Nippon Silica Co., Ltd.), Cabosil (trade name manufactured by Cabot Co., Ltd. in the United States), and Santocel (trade name manufactured by Monsanto Chemical Company in the United States). (product name) etc. are exemplified. These fine powdered silicas have a specific surface area of 50 by BET method.
It is preferable that it is more than ^m2 /g. The blending amount of the fine powder silica is 1 to 40 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the organopolysiloxane. If it is less than 1 part by weight, its performance cannot be fully exhibited, and if it is more than 40 parts by weight, the viscosity of the base oil increases, resulting in poor workability and difficulty in handling. The emulsifier used to form the antifoaming agent of the present invention may be nonionic, cationic, or anionic, but from the viewpoint of the dispersion effect of the antifoaming agent, nonionic emulsifiers are preferred, particularly It is preferable to use a hydrophilic surfactant and a lipophilic surfactant in combination. That is, hydrophilic-lipophilic balance (HLB)
If the HLB is 3 or less, it will not function as a dispersion stabilizer, while if the HLB is 19 or more, the antifoaming properties will be reduced, so a hydrophilic surfactant with an HLB of 8 to 20
A mixture of a lipophilic surfactant with an HLB of 2 to 7 and an HLB of 3 to 19, preferably 4 to 13 is suitable. Surfactants that can be used in the present invention include sorbitan fatty acid esters, glycerin fatty acid esters, sucrose fatty acid esters, higher fatty acid esters of polyoxyethylene compounds, higher alcohol ethers, alkylphenol condensates, and alkyl phenol condensates. Examples include quaternary ammonium salts and higher alkyl sulfonates. In particular, lipophilic surfactants such as sorbitan esters, glycerin esters, propylene glycol esters, or polypropylene glycols of fatty acids having 12 to 18 carbon atoms are preferred, and examples of such active agents include sorbitan monostearate. , sorbitan sesquioleate, monoglycerin monooleate, triglycerin distearate, propylene glycol monolaurate, and the like. In addition, as hydrophilic surfactants, polyoxyethylene esters of fatty acids having 12 to 18 carbon atoms, polyoxyethylene sorbitan esters, polyoxyethylene higher alcohol ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene-polyoxy Preferred are propylene block copolymers, polyoxyethylene castor oil esters, sucrose fatty acid esters, and specific examples thereof include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan distearate, polyoxyethylene glycerin monooleate, Examples include polyoxyethylene cetyl ether, sucrose monostearate, polyoxyethylene nonylphenyl ether, and polyoxyethylene tridecyl ether. The amount of these emulsifiers used must be sufficient to make the silicone oil compound into an emulsion.
The amount is usually 10 to 300 parts by weight, particularly preferably 20 to 200 parts by weight, per 100 parts by weight of component (a). If the amount of component (b) is less than 10 parts by weight per 100 parts by weight of component (a), it will be difficult to emulsify, and even if emulsification is possible, the emulsion stability will be poor, and oil will float over time or silica particles will form. If the amount exceeds 300 parts by weight, the particle size of the resulting emulsion becomes too fine, and the amount of free emulsifier increases, which impairs the antifoaming effect, which is not preferable. To reduce product cost and improve ease of use when adding water to a mixture mainly consisting of component (a) and component (b) to emulsify the phase from W/O type to O/W type. In the present invention, water is added as component (c) in an amount of 10 to 500 parts by weight per 100 parts by weight of component (a). If the amount of component (c) is less than 10 parts by weight based on 100 parts by weight of component (a), emulsification phase inversion will not occur and a W/O emulsion will be formed, which is undesirable, and if it is more than 500 parts by weight,
If the amount of water is too large, the viscosity of the composition to be emulsified decreases, making it impossible to apply sufficient shearing, which is undesirable because the resulting emulsion also has large particle sizes and poor stability. In addition, thickeners such as cellulose ethers such as carboxymethyl cellulose and carboxyethyl cellulose, partially saponified polyvinyl alcohol, crystalline cellulose, and sodium alginate may be added to the antifoaming agent of the present invention, if necessary. The amount of these thickeners added is usually 0 to 20 parts by weight per 100 parts by weight of the silicone oil compound described above. If it exceeds 20 parts by weight, the viscosity of the resulting emulsion will become too high and it will be difficult to handle, and since the component (d) itself is a foam, the antifoaming effect will be poor, which is not preferable. Furthermore, a small amount of a bactericide can be appropriately added to the antifoaming agent of the present invention for the purpose of preservative. Sodium hypochlorite, sorbic acid, etc. are effective disinfectants, and the amount added is 0.05 to 0.5% by weight based on the total amount of component (a), the silicone oil compound, and component (b), the emulsifier. It is preferable to set it as the range of. In the present invention, in order to continuously produce an emulsion type antifoaming agent consisting of the following components (a) to (d), at least three discs are arranged coaxially and at regular intervals on a rotating shaft. It is characterized in that the emulsification operation is continuously performed using a cylindrical container equipped with a shear stirring mechanism consisting of the following structure. FIG. 1 is a schematic sectional view of a cylindrical container equipped with this shear stirring mechanism, and FIGS. 2a and 2b are sectional views taken along line AA in FIG. 1, respectively. In the figure, 1 is a cylindrical container, 2 is a rotating shaft, and 3 is a disc attached to the rotating shaft. It is desirable that at least three or more discs are provided on the rotating shaft. Fig. 2a shows a disc without holes, and Fig. 2b shows a disc with multiple holes 4 through which liquid can pass. It is also possible to combine a disc with no holes at all. At least three discs 3 are required to be installed on the rotating shaft, and five or more discs are generally desirable. The distance (clearance) between the periphery of the disk 3 and the inner surface of the cylindrical container 1 should be 2 cm or less, as if it is too large, the shearing action between them will be insufficient and the desired emulsification will not be achieved. Generally, it is desirable to set it in the range of 0.2 to 1.6 cm. Furthermore, a jacket for temperature regulation may be provided around the outer periphery of the cylindrical container. It should be noted that each component may or may not be premixed in advance, and each component may be supplied at a predetermined ratio to one end of the cylindrical container. The supplied components are shear-mixed while passing between the disks to form a paste. The rotation speed of the stirring mechanism is a shear rate of 50 (1/sec)
It is necessary to have a rotational speed of at least 500 to 1500 (1/sec), but this shearing rate in the present invention shall comply with the following definition. Shearing rate (1/sec) = Circumferential speed of disk (cm/sec)/Clearance (cm) The ingredients that are continuously charged by the above operation are mixed uniformly and finally become a paste-like aqueous liquid. and taken out from the outlet 6. The raw material components are pressed into the feed port 5 using a pump, and the adjustable slit 7
By adjusting the amount of outflow from container 1, the amount inside container 1 is 0.5Kg/cm ² G.
By achieving the above pressurized state, the desired uniform emulsification can be achieved satisfactorily. Of course, the pressure inside the container is determined by the relationship between the amount of raw material supplied and the amount flowing out from the slit, and by adjusting these factors, the pressure inside the container can be maintained at a predetermined value. The preferred range of the pressure inside the container is 1
~4Kg/cm ² G. When operating under the above conditions, the raw material components continuously supplied into the cylindrical container 1 from the inlet 5 are regulated by the amount flowing out from the slit 7, and are As a result of thorough shear stirring, extremely uniform and stable emulsification is achieved. If the pressure inside the container is lower than 0.5 Kg/cm ² G, strong shearing of the raw material components within the cylindrical container 1 will not occur, making it impossible to achieve the desired uniform emulsification. In addition, in order to achieve uniform mixing of the silicone oil compound and water, the cylindrical container 1 is filled with particles having a diameter in the range of 0.5 to 5 mm, such as sand grains, glass beads, alumina particles, tungsten particles, etc. A stirrer may be operated, and by doing so, strong shear stirring is performed. still,
At this time, it is desirable to adjust the slit gap so that the filled particles do not pass through the slit 7 and flow out. The composition of the present invention can be produced by continuously supplying the above-mentioned components (a) to (d) to the above-mentioned emulsifying device at a constant rate; in that case, (a) to
(d) Components may be supplied individually or (a) and (b),
A mixture of (c), (d), a mixture of (a), (b) and (c), (d), a mixture of (a), (b), (d) and (c), (a ), (d) and
Mixture of (b) and (c); Mixture of (a) and (b) and (c) and (d); (a)
and
It is possible to supply a mixture of (b) and (d) in combination with (c), etc. Among these supply methods, (a), (b), and (d) are particularly effective in controlling the emulsion particle size.
A combination of a mixture of (c) and (c) is preferred.
In addition, in this step, the above components (a) to (d) are added in an amount of 5 to 100
Although it is possible to heat the emulsion to any temperature within the range of 0.degree. C., it is preferable to control the temperature during emulsification and dispersion within the range of 30 to 70.degree. C. in order to obtain an emulsion with a uniform and constant particle size. <<Effects of the Invention>> As detailed above, according to the present invention, it is possible to carry out continuous production of an emulsion type silicone antifoaming agent, which has been difficult in the past, and therefore production efficiency can be significantly improved. <<Examples>> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 Trimethylsilyl-terminated dimethylpolysiloxane with a viscosity of 1000 cs at 25°C [trade name KF-96 manufactured by Shin-Etsu Chemical Co., Ltd.] 88.0 kg, fine powder silica [trade name Nipsil VN3 manufactured by Nippon Silica Co., Ltd.] 12.0 kg
Mix uniformly to make silicone oil compound A.
was manufactured. This silicone oil compound A was added as an emulsifier to sorbitan monostearate [trade name Rheodol SP-S10: HLB=3.8, manufactured by Kao Corporation] 25.0 kg and polyoxyethylene sorbitan monooleate [trade name Rheodol TW-O120, manufactured by Kao Corporation: HLB=
15.0〕25.0Kg, carboxymethyl cellulose as thickener [trade name Celogen WS manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
-A] Add 22.0Kg, heat to 80℃ and use a stirrer for 10 minutes.
Premixed for 1 minute. Next, after adjusting this mixture to 65℃, use a metering pump to adjust the rate to 1.7Kg/min, and add 300.0Kg of water at 25℃ to 3.0Kg/min using another metering pump. The mixture was quantitatively supplied from the bottom side into a cylindrical container having seven disks so as to maintain the same speed. The shear stirring was performed using a disc rotation speed: 2000 rpm, a shear rate: 1200 (1/sec), a pressure within the system: 0.7 Kg/cm ² G,
Internal temperature: 40 to 45°C. The viscosity of the white opaque high concentration emulsion a obtained from the outlet of the container was measured using a BM type rotational viscometer.
It was 18000cp (25℃). When the electrical resistance was measured using a tester, it showed conductivity, indicating that the continuous phase is water.
It was confirmed that it was a type emulsion. The active ingredient was 36.2% by weight. This high-concentration emulsion a was stable and did not separate even when stored for 3 months at 40°C. This highly concentrated emulsion
Antifoam emulsion A was obtained by adding 530 kg of dilution water to 470 kg of A and diluting and mixing. The above antifoam emulsion A is a white emulsion containing 17% by weight of the active ingredient and has a viscosity of 500 cp (25% by weight).
°C), volume average particle size is 12.6μm, particle size is 6-18μm
The volume distribution ratio of the particles was sharp at 72.3%, and not only did the silicone oil not float, but it was a stable emulsion that did not separate even when stored at 40°C for 3 months. Comparative Example 1 The rotation of the disk in Example 1 was performed at a shear rate of 40
When stirring and mixing were carried out under the same conditions except that the speed was set to (1/sec), a highly concentrated emulsion b with a viscosity of about 8200 cp (25°C) was obtained. This was diluted with water at the same dilution ratio as in Example 1 to obtain emulsion B. This emulsion has a viscosity of 240 cp (25°C), an average particle size of 21.8 μm, and a particle size of 6 to
The volume distribution ratio of 18μm particles is 26.2%, which is a broad distribution, and oil-like substances float on the liquid surface, causing
When left alone, it completely separated in 3 days. Comparative Example 2 Stirring and mixing were carried out under the same conditions as in Example 1 except that the slit width of the cylindrical container was widened and the system internal pressure was set to 0.3 Kg/cm ² G. The viscosity was approximately 13000 cp (25°C).
A high concentration emulsion c was obtained. This was diluted with water at the same dilution ratio as in Example 1 to obtain antifoam emulsion C. This emulsion c has a viscosity of
320cp (25℃), average particle size is 18.9μm, particle size is 6~
An oily substance floated on the upper liquid surface with a broad volume distribution ratio of 18 μm particles of 30.8%, and when it was left at 40°C, it completely separated in one week. Comparative Example 3 When an attempt was made to emulsify a mixture of the same antifoaming agent composition, emulsifier, and thickener as in Example 1 by stirring and mixing it under the same conditions using a homomixer, the paste-like material was found to have a high viscosity. Because of this, stirring was not possible and an emulsion could not be obtained. Example 2 Terminal trimethylsilyl group-blocked dimethylpolysiloxane [KF
-96〕92.0Kg, Fine powder silica〔Nipsil VN3〕
Silicone oil compound B was manufactured by uniformly mixing 8.0 kg. Rheodol SP-S10, which was used in Example 1 as an emulsifier, was added to this silicone oil compound B.
25.0 kg of Rheodol TW-O120 and 20.0 kg of polypropylene glycol [product name: Uniol D-3000, manufactured by NOF Corporation] were added, and heated to 80°C.
The mixture was heated and mixed by stirring until uniform. This mixture was then quantitatively fed into a mixing apparatus similar to that used in Example 1 at a similar rate. The shear stirring was performed using a disc rotation speed: 2000 rpm, a shear rate: 1200 (1/sec), a pressure within the system: 1.5 Kg/cm ² G,
Internal temperature: 40 to 45°C. As a result, a white, opaque, highly concentrated emulsion d was continuously obtained from the outlet. The viscosity of this emulsion d is
50,000 cp (at 25°C), and remained stable without separation even when stored for 3 months at 40°C. 530 kg of dilution water was added to 470 kg of this high concentration emulsion and diluted and mixed to obtain antifoam emulsion D. The obtained antifoam emulsion D contains the active ingredient
It is a white emulsion with a concentration of 17% by weight and a viscosity of
780cp (25℃), volume average particle size is 10.2μm, particle size is 6
The volume distribution ratio of particles of ~18 μm was sharp at 69.0%, and the emulsion was stable without floating silicone oil and did not separate even after being left standing at 40° C. for 3 months. Comparative Example 4 100 kg of KF-96 with a viscosity of 1000 cs at 25°C, 25.0 kg of Rheodol SP-S10, and 25.0 kg of Rheodol TW-
25.0 g of O120 and 20.0 kg of Uniol D-3000 were added, heated to 80° C., and stirred and mixed until uniform. After adjusting the temperature of this mixture to 65°C, it was transferred to the same apparatus as shown in Example 1 using a metering pump.
It was fed at a feed rate of Kg/min. Further, a solution prepared by dispersing 10 kg of Nipsil VN3 in 290 kg of 25°C water was similarly supplied using another metering pump at a rate of 3.0 kg/min. The shear stirring conditions were the same as in Example 1. As a result, a white, opaque, highly concentrated emulsion e with a viscosity of 5000 cp (25° C.) was continuously obtained from the outlet. Next, this emulsion E was diluted and mixed in the same manner as in Example 1 to obtain an antifoam emulsion E containing 17% by weight of the active ingredient. This emulsion E has a viscosity of 1700 cp (25°C),
The volume average particle size was 3.8 μm, and the volume distribution ratio of particles with a particle size of 6 μm or less was as fine as 92.4%, and although there was no floating silicone oil, if left at 40°C, fine silica powder would be formed within a week. Sedimentation was observed. Example 3 When the emulsions A to E obtained in Examples 1 to 2 and Comparative Examples 1 to 4 were subjected to defoaming tests using the following anionic and nonionic foaming liquids, the results shown in Table 1 were obtained. [Defoaming test using anionic foaming liquid] Weigh out 100g of an ion-exchanged aqueous solution of 0.2% sodium oleate into a measuring cylinder with an internal volume of 1000ml,
Add to this 0.4g of the antifoam emulsion obtained in the example.
The change over time in the amount of foaming was investigated when air was continuously introduced at a rate of 1/min through a glass ball filter after the addition of . The results are shown in Table-1.

[Table] [Defoaming test using nonionic foaming liquid] 0.3% polyoxyethylene nonyl phenyl ether (HLB
= 11.0) 100 g of the ion-exchange aqueous solution was weighed out, 0.1 kg of antifoam emulsion was added, and the change in foaming amount over time was examined in the same manner as above. Table 2 of the results
It was shown to.

[Table] From the results in Tables 1 and 2, it was demonstrated that the antifoaming agent of the present invention is extremely excellent in being able to maintain the antifoaming effect over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal sectional view of a cylindrical container equipped with a shear stirring mechanism. Figure 2 a and b are A- in Figure 1.
It is an A sectional view. 1... Cylindrical container, 2... Rotating shaft, 3... Disk, 4... Hole, 5... Supply port, 6... Product outlet, 7... Slit.

Claims (1)

[Claims] 1 (a) Silicone oil compound consisting of 100 parts by weight of organopolysiloxane and 1 to 40 parts by weight of finely powdered silica: 100 parts by weight (b) Emulsifier: 10 to 300 parts by weight (c) Water: 10 ~500 parts by weight (d) Thickener: A mixture consisting of 0 to 20 parts by weight is continuously supplied into a cylindrical container equipped with a shear stirring mechanism, and the inside of the container is heated to 0.5 Kg/cm ² G.
While maintaining the pressurized state above, the shear rate is 50 (1/
A method for continuous production of an emulsion-type silicone antifoaming agent, which comprises carrying out shear stirring as described above (seconds) and continuously taking out the silicone emulsion from the product outlet of the container.